Allen w



(i 'l i 1o tion. l n

UNITED- STA-TES PATENT OFFICE.

ALLEN w. YRofsE ANDCHAELESA. cHEEvER,'oF NEw YORK, N. Y., AssIeN ons,ABY DIRECT AND M-EsNE ASSIGNMENTS, 'ro SAID cHEEvEn AS.

TRUSTEE. i

ELECTRIC SPEAKING-TELEPHONE.

SPECIFICATION forming part of LettersjPatent No. 272,329, datedFebruary` 13, 1883.

Application nien october 26, Isso. (NQ meer.)

5 CHARLES A. CHEEVER, a citizen of the United States, resldingin NewYork city aforesaid,

jointly have invented certain newv and useful Improvements in ElectricSpeaking-Tele, phones, of which the following is a- 'speciiica-I Ourinvention lis based and constitutes an improvement upon certain new andusefulirn-l pro'vements in electric-telephony and trans-`mitting-telephonesmadeby theaforesaidRose,

I5 the distinguishing characteristic` ofwhich-is the suspension ofmagnetic iilings in the magnetic tield of a speakingfteiephone, throughwhich field agalvanic currentpasses.

The object of our invention is, more espe` zo cially, to adapt such atelephone for operation both'as a transmitter and as a receiver.l

The subject-matter claimed is designated at -the endof thisspecification. v L n The essential features ot' our improved telephoneare a magnet, a helix constituting part of a galvanic circuit andenveloping the core of the magnet or ia portion of it, Iilings of metalssusceptible to magnetic action, suspended in the magnetic field of themagnet, but not 3o necessarily in the circuit, and a diaphragm,

preferably ot' non-magnetic material, between which and the magnet thefilings are interposed. vThe diaphragm is thrown into action asareceiver by the inductive actionof the magnet upon the filings. TheIvariations in the strength of the current produced in the transmitterby sound-vibrations cause correlative variations in such current in themagnet ofthereceiver,which variationsarereproduced 4o through theinterventionot' the filings upon the diaphragm, by the vibrations ofwhich sounds are reproduced. 1

(Jur improvements may readily be adapted to most of the various forms oftransmitting telephones shown in sundry applications for Letters Patentof the United. States filed by the said Rose simultaneously herewith. Wedo not therefore claim anything shown in said applications, but limitourselves to the -im- 5o provenients thereon herein set forth.

0ur ,improved receiver can be operated in connection'with any of the\vell-hnownlbat tery-telephone transmitters. A Themagnetic filings maybeof any magnetic materials, such as iron, steel, aluminum, cobalt, ornickel; but the latteris preferred, as :being less` liable to oxidationfrom moisture'. AThe filings may be employed in the form ofacoarsepowder but'we prefer slivers or ilin gs jof` a length three orfour times greater than their width or thickness, as they interlace more.perfectly, and consequently respond to slighter, vibrations. A mixtureof filings ot' different magnetic metals, or of powder and Iilings ofhomogeneous magnet-ic metals, or of dissimilar magnetic metals, may beused with goodeftect. j In the accompanying drawings, Figure 1`represents a central longitudinal section through ourimproved telephoneorganized for operation vboth as areceiver and as a transmitterwith aninduction-coil included in the circuit.- Fig. 2 shows a Rose transmitterarran'ged on circuit with our improved receiver, the` line beingorganized for transmission in one direction only. u

The drawings show a permanent magnet, M,provided with an enlarged heador plate, m, constituting one of its poles, and properly secured in thecase or handle C. Anordina-ry coil or helix, H, surrounds this core nearthe enlarged pole. The wires of the helix terminate in binding-screwsSYS', in the usual Way.

A diaphragm, D, of some 'non-magnetic ma-l terial, is secured in thecase in the usual way, so as to leave a space between the enlarged poleof the permanent magnet and the diaphragm, which space or magnetic fieldis supplied with magnetic lings such as herein referred to. l

The apparatus thus described (and also particularly shown in Fig. 2) isadapted for operation as a receiver, R, only, and may be placed uponthelinein combination with atransmitter, T, such as those describedinthe Rose application above mentioned, or `any other suitabletransmitter.

The diaphragm D, when used as a transmitter, must be ot some conductingmaterial, not.-

IOC

transmitting-wire, t,is connected with this diaphragm, and the` other,t', with the enlarged pole of the magnet, and said transmittin g-wiresare connected with a battery, B, and the primary wire of theinduction-coil I inusual wellknown ways for this class of instruments,the current passing through the filings. Thehelix H is connected withthe secondary wire of' the induction-coil and with the line in usualwellknown ways. Using this instrument as a transmitter, it operatesprecisely like the Rose transmitter above referred to. The diaphragm Dis thrown into vibration by sound-waves. These vibrations of thediaphragm produce corresponding` variations in the condition ot' themagnetic filings through which the trans` mitting-current passes, th uscausing correlated variations in the strength of thecurrent, which arereproduced upon any suitable receiver in any well-known way. When usedas a receiver the vibrations transmitted through theline act on thehelix of the magnet, thereby causing the magnet to act inductively uponthe filings, producing vibrations therein corresponding with thosereceived through the helix. The vibrations ot the filings impartcorrelative vibrations to the diaphragm, thus producing sound-waves. Thevibrationsofthediaphragm are produced mechanically by direct action ofthe vibrating filings.

Fig. 2 is a diagram showing a transmitter and receiver as arranged oncircuit and adapted for transmission in one direction only. With theline equipped with two instruments such as above described, messagescould be sent either way.

Our improvements lnay be applied to various forms of' transmitters shownin the applications of Rose above mentioned, which involvel the use of adiaphragm or plunger, it being only necessary, to adaptthem for use asreceivers as well as transmitters, to put a helix around the pole of themagnet, so asto act inductively on the filings in a manner similar tothat described in Fig. 1.

A diaphragm of non-inductive or even of non-conductive material-such asmicamay be used as a receiver. The transmitting-diaphragm, as beforeremarked, need'not be of magnetic metal.

We claim as of our own joint invention- I 1. The combination,substantially as herein set forth, ofthe magnet,theinducing-coilconneeted in circuit, the diaphragm, and the magneticfilings interposed in a loose condition in the magneticfield betweensaid diaphragm and pole, of the magnet, and acted upon by induction toreproduce sound-vibrations transmitted through the circuit.

2. The combination, substantially as herein set forth, in a galvaniccircuit, ofa transmitter having the capacity of varying the strength ofthe current by changes in the condition of the metallic filings includedin the circuit, and a receiver consisting of a magnet acting induetivelyupon magnetic filings interposed between said magnet and the diaphragm,andthus varying the intensity ofthe magnetic field in which they areincluded.

3. rlhe transmitting and receiving telephone hereinbefore described,consisting of the combination of the magnet, the helix, itscircuitconnections, the diaphragm, the magnetic filings interposed inthe magnetic field between the magnet and diaphragm, andthe transmit- 75ting circuit-connections, one wire of which is connected with thediaphragm and the other with the magnet, the transmittingcurrent passingthrough the filings, upon which the receiving-current acts inductively.

4. The combination, substantially as herein set forth, of' the magnet,the helix and its circuit-connections,including theseeondary helix of'an induction-coil constituting part of' thc line-wire, the diaphragm,the magnetic filings interposed in the magnetic field between the magnetand diaphragm, and the transmitting circuit-connections, (one ot' whichis connected with the diaphragm and the other with the magnet,)including the primary helix of' said induction-coil.

A. W. ROSE. UHAS. A. GHEEVER. Witnesses WILLARD L. GANDEE, E. C.DAVIDSON.

